You are the procurement officer, the regulatory affairs manager, or the operations director who has been handed four translation quotes and a deadline. Three of them look identical. All four say "certified," "professional," and "native speakers." The cheapest is less than half the most expensive. Which one do you pick, and how would you know if you were wrong before the documents are already filed, printed, or in front of a regulator?
Here is the thing most buyers get wrong at the start: "certified translation agency" is not a defined term. "Certified translation" is a defined deliverable (a translation accompanied by a signed statement of accuracy), but no government body certifies agencies. Any broker can put the word on a website. This guide covers the criteria that actually separate vendors who produce reliable work from those who resell to the lowest bidder.
The Villain: Lowest-Price Procurement
The real enemy is not any one vendor. It is the buying process that rewards the lowest per-word number without checking what was removed to reach it. In translation, the expensive steps are the ones that make the output trustworthy: matching the linguist to the subject matter, having a second qualified person compare the translation against the source, and managing terminology across a project. When a quote is far below the field, one of those steps is usually missing. You will not see it on the invoice. You will see it in a rejected filing, a mistranslated consent form, or a contract clause that says something the original did not.
Criterion 1: ISO 17100 (and What It Actually Guarantees)
ISO 17100 is the international standard for translation services. The current edition is ISO 17100:2015, and ISO has a revision in development, so confirm the edition when you ask. The standard sets requirements for the translation process, including the competence of translators, a revision step performed by a second person who compares the translation with the source, project management, and record keeping. Certification is awarded to the company by an auditor. It is not a credential an individual translator holds.
What it does and does not tell you:
- It does tell you that a documented process exists: qualified translators, a second-person revision, and records of each project.
- It does not tell you that any single translation is perfect, or that the linguist assigned to your file knows your subject. A certificate shows that a system exists to prevent, detect and correct errors, not that errors never occur.
- It is not interchangeable with ISO 9001. ISO 9001 is generic quality management. A vendor holding only ISO 9001 has not been audited against translation-specific requirements.
What to ask: "Send the current certificate and show me the scope statement." Check the expiry date and that the scope names translation services. Then ask the follow-up that matters more: "On my project, who is the translator, who is the reviser, and are they two different people?"
Comparing vendors right now? Send us your project details and we will answer the checklist below in writing, including who translates, who revises, and how your files are handled.
Criterion 2: Machine Translation Needs Its Own Standard
ISO 17100:2015 does not cover raw machine output followed by post-editing. That workflow has its own standard, ISO 18587, which defines requirements for post-editing machine-translated content. If a vendor tells you it uses "AI plus human review," ask which standard the post-editing follows, who performs it, and whether you can opt out of machine translation entirely for regulated or legal content. Our companion piece on when machine translation post-editing is appropriate covers where the line sits. For legal, clinical, immigration, and regulatory documents, the safe default is a fully human workflow.
Criterion 3: The Linguist, Not the Logo
Quality is produced by a specific person translating a specific file. Three credentials are worth asking about, and each has a limit:
| Credential | What it covers | What it does not cover |
|---|---|---|
| ATA certification | An individual translator has passed the American Translators Association exam in one language direction. | It does not certify an agency, and it does not cover other language pairs or subject-matter expertise. |
| Subject-matter background | A linguist with legal, medical, or technical training in the field. | It does not prove translation skill by itself. |
| ISO 17100 translator criteria | Qualifications through education, experience, or equivalent, as required by the standard. | It does not name who is assigned to your project. |
Ask for the credentials of the assigned linguist for your language pair and subject. A vendor that answers "our team is fully certified" without naming anyone has told you nothing.
Criterion 4: Security, Confidentiality, and Subcontractors
Your documents may contain patient data, personal identifiers, unpublished regulatory filings, or contract terms. Before you send a file, ask:
- Will the vendor sign an NDA and, for protected health information, a business associate agreement?
- Who sees the file, and are subcontractors disclosed? A vendor that uses freelancers is not automatically bad, but one that will not tell you is.
- Where is the file stored, and for how long is it retained after delivery?
- Are files ever fed into a public machine translation engine?
Criterion 5: Turnaround, Corrections, and Accountability
Quality promises that are not in the contract are marketing. Look for a stated turnaround by volume, a defined process for correcting errors you report (and how long you have to report them), and a named project contact. For recurring work, ask how terminology is kept consistent across projects, since a glossary and translation memory are what stop the same term being translated three ways in one document set.
The Buyer's Checklist
| Question to ask | A good answer | A warning sign |
|---|---|---|
| Do you hold ISO 17100? | Certificate with scope and expiry, shown on request. | "We follow ISO principles." |
| Who revises my translation? | A second qualified linguist, different from the translator. | "Our project manager proofreads." |
| Do you use machine translation? | Disclosed, optional, aligned to ISO 18587. | Vague or evasive. |
| Who will translate my files? | Named or profiled linguists for my pair and subject. | "Our certified team." |
| Do you use subcontractors? | Yes or no, with NDAs and a data policy. | Refusal to say. |
| What if I find an error? | A written correction process and timeline. | No process, or extra charges to fix their mistake. |
| Why is your quote lower? | A clear explanation (volume, memory reuse). | No explanation. |
Cheap translation is not a discount on the same product. It is usually a different product with the quality steps removed.
Your 3-Step Plan
- Write the requirements before you request quotes. State the document types, languages, subject area, whether certification statements are needed, security needs, and deadlines, so every vendor bids on the same scope.
- Send every vendor the same checklist and require written answers. Score them on process and credentials, then on price. Vendors who answer plainly are usually the ones with nothing to hide.
- Run a paid pilot on a representative file. Have an independent bilingual reviewer compare it against the source before you commit to a volume contract.
Succeed, and you get a vendor whose work holds up under a reviewer's scrutiny. Fail, and you find out when an agency, court, or regulator does.
Why Work With Taika
Language Access Hub, powered by Taika Translations, is a veteran-owned (VOSB), SAM-registered provider holding GSA Schedule and NASPO ValuePoint contracts, working with ATA-certified linguists and an ISO 17100 process. We welcome the checklist above and answer it in writing. Our managed translation services include a dedicated project manager and translation memory for programs that need consistency at volume. If you are weighing vendors, send us the same questions you send everyone else. For what certified translation means in practice, see What Is a Certified Translation?